Method of manufacturing wear-resistant panel of ball

ABSTRACT

In a method of manufacturing wear-resistant panel of ball, a TPU film having a pattern printed on a reverse side thereof is positioned in a mold for suction molding and trimming to form a panel of ball, which is then positioned in another mold for bonding to an injection molded TPU foam, and the bonded TPU film and TPU foam are allowed to cool to complete a three-dimensional panel of ball. Panels of ball so manufactured are then sewed together to form a ball. The TPU film protects the pattern behind it against abrasion and wear, so that the pattern is always fresh and complete to give the ball a distinguishable appearance. The injection molded TPU foam layer gives the panel of ball a high stability in shape to prevent surface folds. The whole process is simplified to reduce the manufacturing cost.

FIELD OF THE INVENTION

The present invention relates to a method of manufacturing wear-resistant panel of ball, and more particularly to a method of manufacturing wear-resistant panel of ball in which a TPU film having a pattern printed on a reverse side thereof is molded and trimmed to form a panel of ball, which is then bonded to injection molded TPU foam in a mold to form a three-dimensional panel of ball having good shape stability and fresh pattern protected by the TPU film against abrasion and wear.

BACKGROUND OF THE INVENTION

In a currently available method of manufacturing a ball for sporting purpose, multiple pieces of identical panels of ball are cut and then glued or sewn together to form a ball. A conventional method of manufacturing the panels of ball generally includes the following procedures: using a layer of foamed polyurethane about 1.2 mm in thickness, which normally includes a layer of 0.4 mm thick PU and a layer of 0.8 mm thick foamed PU, together with a layer of EPDM, which maybe propylene rubber or foamed rubber sheet, as a major material for making the panel of ball; and subjecting the major material to a serial of complicate processing, including pressing, printing, applying protective paint, backing, sizing at a bottom side, baking, adding the EPDM, pressing, sizing, bonding PU to EPDM, hot pressing the bonded PU and EPDM in a mold to form a U-shaped piece, sizing along the edge of the U-shaped piece, baking, forming a flat panel of ball, and positioning the flat panel of ball in a mold with an inner container for steaming to form a three-dimensional spherical piece.

In the above-mentioned process, a pattern is printed on a surface of the finally molded plastic panel of ball, and a layer of clear protective paint about 0.01 mm to 0.02 mm in thickness is then applied over the printed pattern to protect the latter.

When the ball formed with the panels of ball manufactured in the above conventional method has been used over a prolonged time, the clear protective paint applied on the surface of the panels of ball are gradually worn off to expose the printed pattern to external environment. The exposed pattern is subjected to direct frequent abrasion and becomes damaged and smudgy, and is eventually undistinguishable.

As can be seen from the above description, the conventional method for manufacturing the panel of ball includes complicate procedures. The panel of ball tends to be bent and present surface folds in the course of processing. A panel of ball with surface folds is no longer usable. Therefore, the bad yield is very high, the production efficiency is very low, and the quality is uncontrollable in the above conventional method. The ball formed with the panels of ball produced in the above conventional method is easily deformed under long term of compression, and has poor resistance to wear. The pattern printed on the ball surface is easily abraded off to become smudgy. The panel of ball so formed also has low tear strength to indirectly shorten the life of the ball. Therefore, the conventional method of manufacturing panel of ball requires improvement to eliminate the existing drawbacks.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide a method of manufacturing wear-resistant panel of ball, in which a TPU film is printed at a reverse side with a pattern before being bonded to an injection molded layer of TPU foam to form a three-dimensional panel of ball, so that the pattern is protected by the TPU film against wear and always keeps fresh and complete even when the panels of ball is subjected to abrasion to its front.

Another object of the present invention is to provide a method of manufacturing wear-resistant panel of ball, in which TPU foam is injected by way of super critical fluid (SCF) fine foam injection molding to enable a molded panel of ball to have high shape stability and sufficient resilience and toughness to avoid surface folds.

To achieve the above and other objects, the method of manufacturing wear-resistant panel of ball according to the present invention includes the steps of:

-   -   (a) Printing a pattern on a reverse side of a thermoplastic         polyurethane film (TPU film), drying the printed TPU film, and         applying a layer of gold size to a surface of the design;     -   (b) Positioning the TPU film prepared in the above step (a) in a         mold for suction molding, and trimming the molded TPU film;     -   (c) Positioning the trimmed TPU film in a mold for forming a         panel of ball; and     -   (d) Injecting an amount of TPU foam into the panel-forming mold         for the injection molded TPU foam to bond to the TPU film, and         allowing the bonded TPU film and TPU foam to cool to form a         finished product of three-dimensional panel of ball.

In a preferred embodiment of the present invention, an amount of nitrogen is injected along with the TPU foam to give the panel of ball an improved softness and resilience.

More particularly, in the method of the present invention, the TPU film is first printed at a reverse side with a pattern, and then positioned in a mold for suction molding and trimming to form a panel of ball. The molded and trimmed TPU film is then positioned in another mold for molding a panel of ball, and an amount of TPU foam is injected into the mold by way of super critical fluid (SCF) fine foam injection molding to bond to the TPU film, so that the bonded and cooled TPU film and TPU foam form a three-dimensional panel of ball for sewing into a ball.

On the completed ball, since the pattern is located behind and protected by the TPU film, the pattern is not subjected to direct abrasion and wear when the ball rolls and the panels of ball are abraded. That is, the pattern is wear-resistant and always in a fresh and complete state.

Moreover, with the injection molded layer of TPU foam in the method of the present invention, the molded panel of ball has high shape stability without surface folds. And, since the panel of ball is directly molded into a three-dimensional shape by injection molding the TPU foam, the process for forming the panel of ball is largely simplified to increase the productivity and quality while reduce the manufacturing cost.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein

FIG. 1 is a flowchart showing the steps included in the method of manufacturing wear-resistant panel of ball according to the present invention;

FIG. 2 illustrates the process of forming a pattern on a TPU film according to the present invention;

FIG. 3 illustrates the process of suction molding the TPU film in the present invention;

FIG. 4 shows the process of suction molding of FIG. 3 is completed;

FIG. 5 illustrates the positioning of a suction molded TPU film in a mold for forming a panel of ball; and

FIG. 6 shows the finished product of a three-dimensional panel of ball manufactured in the method of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In a method of manufacturing wear-resistant panel of ball according to the present invention, the following steps are included:

-   -   (a) Printing a pattern on a reverse side of a thermoplastic         polyurethane film (TPU film), drying the printed TPU film, and         applying a layer of gold size to a surface of the design;     -   (b) Positioning the TPU film prepared in the above step (a) in a         mold for suction molding, and trimming the molded TPU film;     -   (c) Positioning the trimmed TPU film in a mold for forming panel         of ball; and     -   (d) Injecting an amount of TPU foam into the panel-forming mold         for the injection molded TPU foam to bond to the TPU film, and         allowing the bonded TPU film and TPU foam to cool to form a         finished product of three-dimensional panel of ball.

The method of the present invention for manufacturing a wear-resistant panel of ball according to the present invention is now described in more details as follows.

Please refer to FIGS. 1 and 2. In the step (a), a pre-designed pattern 2 is printed on a reverse side of a clear TPU film 1. When the printed pattern 2 is dried, a layer of polyurethane (PU) gold size 3 is applied to a surface of the printed pattern 2. The PU gold size 3 creates a brilliant and colorful effect on the surface of the printed pattern 2.

Wherein, the TPU film 1 used in the process has a thickness of 0.3 mm.

Please refer to FIGS. 3 and 4. In the step (b), the TPU film 1 having the pattern 2 printed on a reverse side thereof is positioned in a mold 5. And, a molding apparatus 4 is used to proceed with the process of suction molding and trimming, so that the TPU film 1 is molded and trimmed to form a three-dimensional panel of ball.

Please now refer to FIGS. 5 and 6. In the step (c), the molded and trimmed TPU film 1 is positioned in a panel-forming mold 6 with the printed pattern 2 facing upward, so that the TPU film 1 is ready for the subsequent injection molding process.

In the step (d), the TPU foam 7 is injected into the mold 6 via an injecting orifice, so that the TPU foam 7 and the TPU film 1 are bonded together under high temperature. When the bonded TPU foam 7 and TPU film 1 are cooled, the finish product of a three-dimensional panel of ball is formed.

In an ideal embodiment of the present invention, the injection molded TPU foam 7 in the step (d) has a thickness of 4 mm.

In a preferred embodiment of the present invention, in the step (d) of injection molding the TPU foam 7, a predetermined amount of Nitrogen is injected at the same time to give the finished panel of ball an improved softness and resilience.

It is noted the TPU foam 7 being injection molded in the step (d) may be replaced with other suitable materials.

The finished three-dimensional panels of ball are then sewn together manually or using a seamless process to complete a ball.

On the completed ball, since the pattern 2 is printed on the reverse side of the TPU film 1 before injection molding each panel of ball, the pattern 2 is located behind the TPU film 1 when the panel of ball is molded. When the ball rolls and is subjected to abrasion of a front surface thereof, the pattern 2 is protected by the TPU film 1 against direct abrasion and can therefore keep its freshness and integrity.

With the method of manufacturing a panel of ball by injection molding a layer of TPU foam 7 behind the TPU film 1, the molded panel of ball has a high stability in shape without showing surface folds, and has good resilience and sufficient toughness. Since the panel of ball is directly formed into the three-dimensional shape by injection molding, the manufacturing process is simplified, compared to the method of prior art. The problem of surface folds presented on the panel of ball due to being bent in the process can therefore be avoided. The simplified manufacture process not only upgrades the quality of the produced panel of ball and reduces the manufacturing time, but also largely reduces the costs for manufacturing apparatus and material preparation.

The wear-resistant panel of ball manufactured in the method of the present invention does not involve complicate processing procedures and has improved foam resilience and wear-resistance. The simplified manufacturing process also reduces the bad yield of the panel of ball to upgrade the productivity and quality thereof. The ball produced with the panels of ball manufactured in the method of the present invention does not easily deform under long term of compression, has excellent bending strength, and reduces the possibility of causing injury to people being hit by the ball. Moreover, since the TPU film has good wear-resistance, tear strength, and tensile property, it advantageously extends the life of the ball made using the method of the present invention.

The present invention has been described with some preferred embodiments thereof and it is understood that many changes and modifications in the described embodiments can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims. 

1. A method of manufacturing wear-resistant panel of ball, comprising the steps of: (a) Printing a pattern on a reverse side of a thermoplastic polyurethane film (TPU film), drying the printed TPU film, and applying a layer of gold size to a surface of the pattern; (b) Positioning the TPU film prepared in the above step (a) in a mold for suction molding, and trimming the molded TPU film; (c) Positioning the trimmed TPU film in a mold for forming panel of ball; and (d) Injecting an amount of TPU foam into the panel-forming mold for the TPU foam to bond to the TPU film, and allowing the bonded TPU film and TPU foam to cool and form a finished product of three-dimensional panel of ball.
 2. The method of manufacturing wear-resistant panel of ball as claimed in claim 1, wherein said TPU film has a thickness of 0.3 mm.
 3. The method of manufacturing wear-resistant panel of ball as claimed in claim 1, wherein the TPU foam being injection molded in the step (d) has a thickness of 4 mm.
 4. The method of manufacturing wear-resistant panel of ball as claimed in claim 1, wherein a predetermined amount of nitrogen is injected along with the TPU foam in the step (d).
 5. The method of manufacturing wear-resistant panel of ball as claimed in claim 1, wherein the TPU foam being injection molded in the step (d) is replaceable with other equivalent materials. 